Upvote:2
I did a search for some help and noticed that many UK universities have a student welfare department that offers some help with Tier 4 applications (https://www.google.com/search?q=uk+visa+tier+4+travel+history&oq=uk+visa+tier+4+travel+history&ie=UTF-8). Of those that I cared to look at, the most helpful seemed to be this from the University of Oxford's "Guide to completing Tier 4 (General) Student Online Application" (last updated 1 Mar 2018):
International Travel History
You are asked to record visits to a list of five countries plus the Schengen area in the past 10 years.
Follow the instructions and if you cannot remember all of them, include this information in the ‘additional information’ section at the end of the formThe form continues to ask about travel to all other counties. Again answer this to the best of your ability and if you are a frequent traveller include this in the ‘additional information’ section at the end
Maybe your university offers some specific advice and be aware that advice might change at any time.